ASSESSMENT OF METHANE ESTIMATION FROM VOLATILE FATTY ACID STOICHIOMETRY IN THE RUMEN IN VITRO
Abstract: Rumen microbes
breakdown feed to produce volatile fatty acids (VFA), carbon dioxide,
ammoniaand methane (CH4). Metabolic hydrogen in the form of reduced protons is
used during CH4 formation aswell as during VFA synthesis. Therefore, VFA
concentration in the rumen may stoichiometrically berelated to CH4 emission.
The aim of this study was to evaluate methane emission between experimentaland
model estimates. Two stoichiometrical models for predicting CH4 from VFA were
assessed, i.e.Moss et al. (2000) and Hegarty and Nolan (2007) models. The data
sets were obtained from a publishedliterature. Samples used were leaves from 27
tropical plant species. Prediction error was conducted bycomputing root mean
square prediction error (RMSPE). Results showed that estimation model of Mosset
al. (2000) had lower RMSPE value, i.e. 8.01%, than that of Hegarty and Nolan
(2007) model, i.e.10.73%. Variation of methane emission, i.e. the low or high
methane can be estimated by VFAcomposition with a sufficient accuracy. Adjusment
by considering H2 recovery lowered the biassignificantly. It can be concluded
that Moss model had better accuracy in predicting CH4 emission fromVFA
composition than that of Hegarty and Nolan model.
Author: A. Jayanegara, I.
Ikhsan, T. Toharmat
Journal Code: jppeternakangg130049